Hydraulic pressure control device and method for controlling brake hydraulic pressure control unit

Abstract

The present invention inhibits an output current from becoming excessive and prevents a function of automatic brake control from being stopped when an automatic brake control function is operated by a supply current from an auxiliary power supply. In a hydraulic pressure brake system (1) comprising an electric brake booster (10), a brake hydraulic pressure control unit (20), a main power supply (5) that supplies electric power to the electric brake booster (10) and the brake hydraulic pressure control unit (20), and an auxiliary power supply (7) that supplies electric power to the brake hydraulic pressure control unit (20) when an abnormality occurs in the main power supply (5), the hydraulic pressure control device (90) limits the upper limit of the rotational speed of motor pumps (63a, 63b) of the brake hydraulic pressure control unit (20) when the function of the automatic brake control is in the activated state and an abnormality occurs in the main power supply (5).

Description

[0001] [Document name] Statement

[0002] [Title of invention] Hydraulic pressure control device and control method for brake hydraulic pressure control unit

[0003] [Technical Field]

[0004]

[001] The present disclosure relates to a hydraulic pressure control device and a control method for a brake hydraulic pressure control unit.

[0005] [Background technology]

[0006] [. 0 0 2] The vehicle is equipped with a hydraulic brake system. The hydraulic brake system has a brake hydraulic control unit equipped with a motor pump and multiple control valves, and the hydraulic control device controls the drive of the brake hydraulic control unit, thereby adjusting the brake hydraulic pressure supplied to each wheel. The brake hydraulic control unit is used for brake control such as automatic brake control, emergency brake control, and electronic stability program (ESP) control.

[0007]

〇 0 0 3

[0008]

[0004] One type of system that utilizes the function of automatic brake control is a remote control system that remotely controls the driving operation of a vehicle. For example, Patent Document 1 discloses, as one aspect of the remote control system, a remote parking system in which a user operates a mobile terminal or the like while out of the vehicle to remotely park the vehicle in a predetermined position. While the vehicle is being driven by the remote control system, an automatic brake function is activated to stop the vehicle or to prevent the vehicle from coming into contact with people or objects approaching the vehicle.

[0009] [Prior art documents]

[0010] [Patent documents]

[0011]

〇 0 0 5

[0012] [Patent Document 1] Japanese Patent Application Laid-Open No. 2021-49845

[0013] Summary of the Invention

[0014] [Problem to be solved by the invention]

[0015] [0 0 0 6] If the power supply to the brake fluid pressure control unit is cut off while the vehicle is being remotely operated without the driver present, braking force cannot be generated. To address this issue, it is possible to provide an auxiliary power supply separate from the main power supply that supplies power to the brake fluid pressure control unit, and in the event of a main power supply abnormality, the auxiliary power supply can supply power to the brake fluid pressure control unit, thereby ensuring a power supply to the brake fluid pressure control unit.

[0016] [0 0 7] However, the capacity of the auxiliary power supply is often smaller than that of the main power supply. For this reason, if the motor pump of the brake fluid pressure control unit runs at full speed when the automatic brake is activated, the output current from the auxiliary power supply will become excessive, causing the auxiliary power supply voltage to drop, and the fail-safe function of the brake fluid pressure control unit may stop the automatic brake control function. For example, if the automatic brake control function stops when the vehicle is on a slope and the driver is not present, the vehicle may not be able to be stopped and may collide with another vehicle, etc.

[0017] [0 0 0 8] The present disclosure has been made in consideration of the above problems, and provides a hydraulic control device and a control method for a brake hydraulic control unit that can suppress excessive output current and prevent the automatic brake control function from stopping when the automatic brake control function is activated by current supplied from an auxiliary power source.

[0018] [Means for solving the problem]

[0019]

[0009] In order to solve the above problem, according to an aspect of the present disclosure, there is provided a hydraulic brake system including: an electric brake booster that boosts a brake pedal force applied by a driver to pressurize brake fluid in a master cylinder; a brake fluid pressure control unit that includes a motor pump and a plurality of control valves and adjusts brake fluid pressure generated in each wheel of a mobile body by the brake fluid supplied from the master cylinder; a main power supply that is electrically connected to the electric brake booster and the brake fluid pressure control unit and supplies power to the electric brake booster and the brake fluid pressure control unit; and an auxiliary power supply that is connected to the brake fluid pressure control unit and supplies power to the brake fluid pressure control unit when an abnormality occurs in the main power supply. In this hydraulic control device, the hydraulic brake system includes: a first determination unit that determines an activation state of an automatic brake control function that automatically controls the brakes of the mobile body; a second determination unit that determines whether an abnormality has occurred in the main power supply; and an output limiting section that limits the upper limit of the rotation speed of the motor pump of the brake hydraulic control unit when it is determined that the brake function is in an activated state and that an abnormality has occurred in the main power supply.

[0020]

[0010] To solve the above problem, according to another aspect of the present disclosure, there is provided a control method for controlling drive of a brake fluid pressure control unit in a hydraulic brake system including: an electric brake booster that boosts a brake pedal force applied by a driver to pressurize brake fluid in a master cylinder; a brake fluid pressure control unit that includes a motor pump and a plurality of control valves and adjusts brake fluid pressure generated in each wheel of a mobile object by the brake fluid supplied from the master cylinder; a main power source that is electrically connected to the electric brake booster and the brake fluid pressure control unit and supplies power to the electric brake booster and the brake fluid pressure control unit; and an auxiliary power source that is connected to the brake fluid pressure control unit and supplies power to the brake fluid pressure control unit when an abnormality occurs in the main power source, the control method comprising: a step of determining an activation state of an automatic brake control function that automatically controls brakes of the mobile object; a step of determining whether an abnormality has occurred in the main power source; and when it is determined that an abnormality has occurred in the main power supply, limiting the upper limit of the rotation speed of the motor pump of the brake hydraulic pressure control unit.

[0021] [Effects of the Invention]

[0022] [0 0 1 1] As described above, according to the present disclosure, when the automatic brake control function is activated by the supply current from the auxiliary power supply, it is possible to prevent the output current from becoming excessive and to prevent the automatic brake control function from stopping.

[0023] BRIEF DESCRIPTION OF THE DRAWINGS

[0024] [ 0 0 1 2 ]

[0025] [Figure 1] An explanatory diagram showing an example of the configuration of a hydraulic brake system equipped with a hydraulic pressure control device according to an embodiment of the present disclosure.

[0026] [Figure 2] An explanatory diagram showing in detail an example configuration of a hydraulic brake system according to the embodiment.

[0027] [Figure 3] A block diagram showing the control system of a hydraulic brake system equipped with the hydraulic control device according to the same embodiment.

[0028] FIG. 4 is a flowchart showing an example of an output limiting process performed by the hydraulic pressure control device according to the embodiment.

[0029] [Figure 5] An explanatory diagram showing the function of the reference example.

[0030] [Figure 6] An explanatory diagram showing the operation of the hydraulic control device of the same embodiment.

[0031] DETAILED DESCRIPTION OF THE INVENTION

[0032]

[0013] Preferred embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. In this specification and drawings, components having substantially the same functional configurations are designated by the same reference numerals, and redundant description will be omitted.

[0033] [ 0 0 1 4 ]

[0034] <1. Hydraulic Brake System> First, a configuration example of a hydraulic brake system including a hydraulic control device according to an embodiment of the present disclosure will be described.

[0035]

[0015] Fig. 1 is a schematic diagram showing an example of the configuration of a vehicle hydraulic brake system 1. The hydraulic brake system 1 shown in Fig. 1 is a brake system for a four-wheeled automobile, which is one type of moving body. The hydraulic brake system 1 includes an electric brake booster 10, a master cylinder 14, and a brake hydraulic pressure control unit 20. The hydraulic brake system 1 also includes a hydraulic pressure control device 90 that controls the brake hydraulic pressure control unit 20, and a booster control device 100 that controls the electric brake booster 10.

[0036]

[0016] In the hydraulic brake system 1, the force applied to the brake pedal 11 is amplified by the electric brake booster 10 and transmitted to the master cylinder 14. A reservoir tank 60 that supplies brake fluid to the master cylinder 14 is attached to the top of the master cylinder 14. When the driver depresses the brake pedal 11, the brake fluid stored in the master cylinder 14 is pressurized and supplied to the brake fluid pressure control unit 20.

[0037]

[0017] The electric brake booster 10 includes an electric motor. When the driver depresses the brake pedal 11, the booster control device 100 supplies current to the stator of the electric motor, boosting the depression force of the brake pedal 11 and transmitting the boosted force to the master cylinder 14.

[0038]

[0018] The master cylinder 14 is connected to the wheel cylinder of each wheel 3 via a hydraulic circuit provided in a brake hydraulic control unit 20. Braking force is generated at each wheel 3 by the hydraulic pressure supplied to the wheel cylinder of each wheel 3. The brake hydraulic control unit 20 is equipped with a motor pump and a control valve. A hydraulic pressure control device 90 controls the drive of the motor pump and the control valve, and controls the hydraulic pressure supplied to the wheel cylinder of each wheel 3.

[0039]

[0019] The hydraulic control device 90 and the booster control device 100 are each partially or entirely composed of a microcomputer or microprocessor unit including a central processing unit (CPU). The hydraulic control device 90 and the booster control device 100 may be partially or entirely composed of updatable firmware or the like, or may be a program module executed by command from a CPU or the like.

[0040]

[0020] A main power supply 5 is connected to the electric brake booster 10 and the brake fluid pressure control unit 20. The main power supply 5 is, for example, a battery rated at 12 V, and is connected so as to be able to supply current to the electric brake booster 10 and the brake fluid pressure control unit 20 via the booster control device 100 and the fluid pressure control device 90. The booster control device 100 and the fluid pressure control device 90 control the current supplied to the electric motor of the electric brake booster 10 and the motor pump and control valve of the brake fluid pressure control unit 20, respectively.

[0041]

[0021] An auxiliary power supply 7 is also connected to the brake fluid pressure control unit 20. The auxiliary power supply 7 is, for example, a battery rated at 12 V, and is connected to the brake fluid pressure control unit 20 so as to be able to supply current to the brake fluid pressure control unit 20 via a fluid pressure control device 90. In the event of an abnormality in the main power supply 5, the fluid pressure control device 90 controls the current supplied from the auxiliary power supply 7 to the motor pump and control valve of the brake fluid pressure control unit 20.

[0042]

[0022] Fig. 2 is an explanatory diagram showing in detail an example configuration of a hydraulic brake system 1. The hydraulic brake system 1 is configured as a brake system having two brake systems, each of which controls the braking force for one front wheel and one rear wheel as a pair. The hydraulic brake system 1 may be a brake system with a so-called X-type piping arrangement, in which each of the two brake systems controls the braking force for one front wheel and a rear wheel diagonally opposite the front wheel as a pair. Alternatively, the hydraulic brake system 1 may be a brake system with a so-called H-type piping arrangement, in which one system controls the braking force for the left front and rear wheels, and the other system controls the braking force for the right front and rear wheels.

[0043]

[0023] The hydraulic pressure control device 90 and the booster control device 100 are configured to be able to communicate with each other via a communication bus 140 such as a CAN (Controller Area Network). The hydraulic pressure control device 90 and the booster control device 100 are also configured to be able to communicate with a driving assistance device 110 via the communication bus 140. The driving assistance device 110 is configured to be able to acquire information detected by one or more sensors 111 for detecting the environment around the vehicle, such as other vehicles, pedestrians, bicycles, obstacles, etc. The sensor 111 includes, for example, at least one of a camera, a radar sensor, a LiDAR (Light Detection And Ranging), and an ultrasonic sensor.

[0044]

[0024] The driving assistance device 11〇 is configured with a microcomputer or microprocessor unit including an arithmetic processing device such as a CPU or a GPU (Graphics Processing Unit). Part or all of the driving assistance device 11〇 may be configured with updatable firmware or the like, or may be a program module executed by instructions from the CPU or the like.

[0045]

[0025] The driving assistance device 110 is configured to be able to execute automatic brake control (emergency brake control) to prevent the vehicle from colliding with other vehicles or obstacles, or to reduce the impact of a collision. For example, the driving assistance device 110 sets a brake torque command value based on information on the distance to an obstacle, etc. detected by the sensor 111, information on the relative speed between the obstacle, etc. and the vehicle, and information on the vehicle speed, and transmits the information on the command value to the hydraulic pressure control device 90.

[0046]

[0026] The driving assistance device 110 is also configured to be able to execute adaptive cruise control (ACC) control, which utilizes the automatic brake control function to automatically cause the vehicle to follow the preceding vehicle while maintaining a predetermined inter-vehicle distance. For example, the driving assistance device 110 sets a control instruction value for the acceleration / deceleration of the vehicle based on information on the distance to the preceding vehicle detected by the sensor 111, information on the target inter-vehicle distance, information on the relative speed between the preceding vehicle and the vehicle, and information on the vehicle speed, and transmits the information on the control instruction value to a control device that controls the acceleration / deceleration. When decelerating the vehicle, the driving assistance device 110 sets a brake torque instruction value and transmits the information on the instruction value to the hydraulic pressure control device 90.

[0047]

[0027] The driving assistance device 110 is configured to be able to communicate with a mobile terminal (not shown) as a control that utilizes the automatic brake control function, and is configured to be able to execute remote control of the vehicle based on operation signals acquired from the mobile terminal. For example, the driving assistance device 110 sets control instruction values ​​for the acceleration / deceleration and steering angle of the vehicle according to the operation signals acquired from the mobile terminal, and transmits information on the control instruction values ​​to the control devices that control the acceleration / deceleration and steering angle. The driving assistance device 110 executes automatic brake control (emergency brake control) to avoid the vehicle colliding with an obstacle, etc., even during remote operation of the vehicle.

[0048]

[0028] Within the master cylinder 14, two pressure chambers, a primary chamber 47 and a secondary chamber 48, are formed, which are separated by a primary piston 43 and a secondary piston 44. When the driver depresses the brake pedal 11, the primary piston 43 and the secondary piston 44 are pressed, pressurizing the brake fluid stored in the primary chamber 47 and the secondary chamber 48, and the brake fluid is supplied into the brake fluid pressure control unit 20.

[0049]

[0029] The pedal force amplified by the electric brake booster 10 is transmitted to the master cylinder 14 via the push rod 13 that abuts against the primary piston 43. Axial movement of the primary piston 43 also moves the secondary piston 44 in the axial direction. This pressurizes the brake fluid in the primary chamber 47 and the secondary chamber 48.

[0050]

[0030] The electric motor provided in the electric brake booster 10 may be, for example, a brushless DC-DC motor including a stator as a fixed element and a rotor as a movable element. The electric motor is a motor that can rotate forward to advance the push rod 13 and reverse to retract the push rod 13 by switching the direction of current.

[0051]

[0031] A first hydraulic circuit 28 and a second hydraulic circuit 30 extend from the primary chamber 47 and the secondary chamber 48 of the master cylinder 14 respectively to the wheel cylinders 38a to 38d of each wheel 3. The hydraulic circuits of the hydraulic brake system 1 according to this embodiment are of an X-piping type, and brake fluid is supplied to the wheel cylinder 38a of the right front wheel 3RF and the wheel cylinder 38b of the left rear wheel 3LR via the first hydraulic circuit 28. Brake fluid is also supplied to the wheel cylinder 38c of the left front wheel 3LF and the wheel cylinder 38d of the right rear wheel 3RR via the second hydraulic circuit 30. Braking force is generated on each wheel 3 by hydraulic pressure supplied to each wheel cylinder 38a to 38d.

[0052]

[0032] The brake fluid pressure control unit 20 has a first hydraulic circuit 28 and a second hydraulic circuit 30 having the same configuration. Brake fluid is supplied to the first hydraulic circuit 28 and the second hydraulic circuit 30 from the master cylinder 14. Below, we will briefly explain the first hydraulic circuit 28, and will not explain the second hydraulic circuit 30.

[0053]

[0033] The first hydraulic circuit 28 includes, as solenoid valves, a normally open, linearly controllable circuit control valve 36a, a normally closed, on / off controlled suction valve 34a, normally open, linearly controllable pressure increase valves 58aa, 58ba, and normally closed, on / off controlled pressure reduction valves 54aa, 54ba. The first hydraulic circuit 28 also includes a motor pump 63a driven by a pump motor 61, a low-pressure accumulator 71a, and a damper 73a. The number of motor pumps 63a is not limited to one.

[0054]

[0034] The first pressure increase valve 58aa and first pressure reduction valve 54aa, which are provided adjacent to the wheel cylinder 38a of the right front wheel 3RF, and the second pressure increase valve 58ba and second pressure reduction valve 54ba, which are provided adjacent to the wheel cylinder 38b of the left rear wheel 3LR, are used for automatic brake control.

[0035] The first pressure increase valve 58aa for the right front wheel 3RF is provided between the circuit control valve 36a and the wheel cylinder 38a of the right front wheel 3RF. The linearly controllable first pressure increase valve 58aa linearly adjusts the flow rate of brake fluid from the circuit control valve 36a side to the wheel cylinder 38a side of the right front wheel 3RF. The first pressure booster valve 58aa allows brake fluid to flow from the wheel cylinder 38a side to the circuit control valve 36a side when the first pressure booster valve 58aa is closed, but has a bypass flow path equipped with a check valve that restricts flow in the opposite direction.

[0055]

[0036] The first pressure reducing valve 54aa for the right front wheel 3RF is a solenoid valve that can be switched between a fully open and a fully closed position, and is located between the wheel cylinder 38a for the right front wheel 3RF and the low-pressure accumulator 71a. When open, the first pressure reducing valve 54aa reduces the pressure of the brake fluid supplied to the wheel cylinder 38a for the right front wheel 3RF. The first pressure reducing valve 54aa adjusts the flow rate of brake fluid flowing from the wheel cylinder 38a for the right front wheel 3RF to the low-pressure accumulator 71a by repeatedly opening and closing the valve intermittently.

[0056]

[0037] The second pressure increase valve 58ba for the left rear wheel 3LR is provided between the circuit control valve 36a and the wheel cylinder 38 of the left rear wheel 3LR. The linearly controllable second pressure increase valve 58ba linearly adjusts the flow rate of brake fluid from the circuit control valve 36a side to the wheel cylinder 38b side of the left rear wheel 3LR. When the second pressure increase valve 58ba is closed, the second pressure increase valve 58ba allows brake fluid to flow from the wheel cylinder 38b side to the circuit control valve 36a side, while also having a bypass flow path equipped with a check valve that restricts reverse flow.

[0057]

[0038] The second pressure reducing valve 54ba for the left rear wheel 3LR is a solenoid valve that can be switched only between a fully open or fully closed position, and is provided between the wheel cylinder 38b for the left rear wheel 3LR and the low-pressure accumulator 71a. When the second pressure reducing valve 54ba is open, it reduces the pressure of the brake fluid supplied to the wheel cylinder 38b for the left rear wheel 3LR. The second pressure reducing valve 54ba adjusts the flow rate of brake fluid flowing from the wheel cylinder 38b for the left rear wheel 3LR to the low-pressure accumulator 71a by repeatedly opening and closing the valve intermittently.

[0058]

[0039] The circuit control valve 36a is provided to establish or block communication between the booster valves 58aa, 58ba and the master cylinder 14. The suction valve 34a is provided to establish or block communication between the master cylinder 14 and the suction side of the motor pump 63a. A hydraulic pressure sensor 24 is provided in the pipelines between the circuit control valve 36a and the master cylinder 14, as well as between the suction valve 34a and the master cylinder 14.

[0059]

[0040] The second hydraulic circuit 30 supplies brake fluid pressure to the wheel cylinder 38c of the left front wheel 3LF and the wheel cylinder 38d of the right rear wheel 3RR. The second hydraulic circuit 30 is configured in the same way as the first hydraulic circuit 28, except that the wheel cylinder 38a of the right front wheel 3RF in the first hydraulic circuit 28 is replaced with the wheel cylinder 38c of the left front wheel 3LF, and the wheel cylinder 38b of the left rear wheel 3LR is replaced with the wheel cylinder 38d of the right rear wheel 3RR.

[0060] [ 0 0 4 1 ]

[0061] <2. Control System of Hydraulic Brake System> Next, the control system of the hydraulic brake system will be explained. Fig. 3 is a block diagram showing the configuration of the control system related to automatic brake control in the vehicle hydraulic brake system 1. The hydraulic brake system 1 includes a driving assistance device 110, a power management device 120, a booster control device 100, and a hydraulic control device 90, which are communicatively connected via a communication bus 140 such as a CAN.

[0062]

[0042] The driving assistance device 110 determines whether braking is necessary and calculates a brake torque command value based on information about the surroundings of the vehicle detected by a sensor 111, such as a camera, a radar sensor, an LIDAR, or an ultrasonic sensor, and transmits a brake request signal including information about the brake request and the brake torque command value to the hydraulic pressure control device 90. The brake torque command value may be a brake hydraulic pressure command value.

[0063]

[0043] In this embodiment, the driving assistance device 110 is configured to be able to execute at least emergency braking control and remote operation (parking) control. The driving assistance device 110 may be divided into multiple devices for each control to be executed. Since the emergency braking control and remote operation (parking) control may be publicly known controls, a description of the specific processing content will be omitted. When executing controls such as emergency braking control and remote operation (parking) control, the driving assistance device 110 transmits information to the hydraulic control device 90 indicating that the respective controls are being executed.

[0064]

[0044] The power management device 120 detects abnormalities in the main power supply 5 and the auxiliary power supply 7. For example, the power management device 120 detects the voltage and output current of the main power supply 5 and the auxiliary power supply 7, and detects abnormalities in the main power supply 5 and the auxiliary power supply 7 based on the detected voltage and output current. When the power management device 120 detects an abnormality in the main power supply 5 or the auxiliary power supply 7, it transmits information indicating the abnormality in the main power supply 5 or the auxiliary power supply 7 to the hydraulic control device 90. The power management device 120 may be any device that has the function of detecting abnormalities in the main power supply 5 and the auxiliary power supply 7, and a control device equipped in a vehicle with other functions may function as the power management device 120.

[0065]

[0045] The booster control device 100 controls the drive of the electric brake booster 10. Specifically, the booster control device 100 controls the drive of the electric motor of the electric brake booster 10, and moves the push rod 13 forward or backward relative to the master cylinder 14 according to the amount of depression of the brake pedal 11 by the driver.

[0066]

[0046] The hydraulic control device 90 controls the braking force of each wheel 3 by controlling the brake hydraulic control unit 20. The hydraulic control device 90 functions as an ESP control device (anti-skid device) that performs anti-skid control. The hydraulic control device 90 also functions as a control device for an anti-lock brake system (ABS) that prevents each wheel 3 from locking when the driver brakes suddenly.

[0067]

[0047] In this embodiment, the hydraulic control device 90 controls the braking force of each wheel 3 based on a brake request signal generated by emergency braking control and remote operation control executed by the driving assistance device 110. Alternatively, the hydraulic control device 90 may control the braking force of each wheel 3 based on a brake request signal generated by ACC control or automatic driving control executed by the driving assistance device 110.

[0068]

[0048] The hydraulic pressure control device 90 converts the target value of the brake torque required for each automatic brake control into a target value of the brake hydraulic pressure and controls the operation of the brake hydraulic pressure control unit 20. The hydraulic pressure control device 90 drives the pump motor 61 and multiple control valves of the brake hydraulic pressure control unit 20 to supply brake fluid from the master cylinder 14 to the wheel cylinder 38 of each wheel 3 and also discharges brake fluid from the wheel cylinder 38 of each wheel 3, thereby adjusting the brake hydraulic pressure of each wheel 3.

[0069] Furthermore, in this embodiment, the hydraulic control device 90 has a function of transmitting an operation command to an APB (Automatic Parking Braking) device 130, which electrically activates the parking brake under certain conditions when the vehicle is stopped. For example, when the brake pedal 11 is depressed and the vehicle finally stops, the hydraulic control device 90 automatically transmits an operation command to the APB device 130, and when the brake pedal 11 is released, transmits a release command to the APB device 130. In the hydraulic brake system 1 according to this embodiment, the auxiliary power supply 7 is connected to the hydraulic control device 90, so the hydraulic control device 90 can transmit a command to the APB device 130 even when an abnormality occurs in the main power supply 5.

[0070] <3. Hydraulic pressure control device> Next, the hydraulic pressure control device 90 according to this embodiment will be described in detail.

[0071]

[0050] As shown in Fig. 3, the hydraulic control device 90 includes a target brake torque setting unit 91, a drive control unit 92, an APB (automatic parking brake) control unit 93, a safety function unit 94, a first determination unit 95, a second determination unit 96, a power supply switching unit 97, and an output limiting unit 98. The target brake torque setting unit 91, the drive control unit 92, the APB control unit 93, the safety function unit 94, the first determination unit 95, the second determination unit 96, the power supply switching unit 97, and the output limiting unit 98 are functions realized by the execution of a program by a microcomputer. The target brake torque setting unit 91, the drive control unit 92, the APB control unit 93, the safety function unit 94, the first judgment unit 95, the second judgment unit 96, the power supply switching unit 97 and a portion of the output limiting unit 98 may be configured using analog circuits or the like.

[0072]

[0051] In addition, the hydraulic pressure control device 90 includes peripheral components (not shown) and memory elements such as RAM (Random Access Memory) and ROM (Read Only Memory). A portion of the memory elements is used as a work area for the processor that constitutes the microcomputer.

[0073]

[0052] In addition to the brake hydraulic control unit 20, various sensors are connected to the hydraulic control device 90, such as a rotation sensor 81 that measures the rotation speed of each wheel 3, a vehicle speed sensor 83, and an angular velocity sensor 85 that detects the angular velocity of the yaw angle, pitch angle, and roll angle of the vehicle body. These sensors may be directly connected to the hydraulic control device 90, or may be connected to other control devices that can communicate with it via the communication bus 140. In addition, an APB device 130 is connected to the hydraulic control device 90.

[0074] [ 0 0 5 3 ]

[0075] (Target brake torque setting unit) The target brake torque setting unit 91 sets a target value for the brake torque. In ESP control and ABS control, the target brake torque setting unit 91 sets a target value for the brake torque for each wheel 3 based on the sensor signals of various sensors 81 to 85. Furthermore, when the target brake torque setting unit 91 receives a brake request signal transmitted from the driving assistance device 11〇, it sets a target value for the brake torque for each wheel 3 based on the brake torque instruction value contained in the brake request signal. There is no particular limitation on the method for calculating the target value of the brake torque.

[0076] [ 0 0 5 4 ]

[0077] (Drive control unit) The drive control unit 92 controls the drive of the brake fluid pressure control unit 20 based on the target value of the brake torque set by the target brake torque setting unit 91. Specifically, the drive control unit 92 calculates the target value of the brake fluid pressure to be generated in the wheel cylinder 38 of each wheel 3 based on the target value of the brake torque, and controls the drive of the pump motor 61 of the brake fluid pressure control unit 20 and each control valve (34, 36, 54, 58).

[0078] For example, the drive control unit 92 determines a target value of brake fluid pressure corresponding to the target value of brake torque by referring to map information in which the relationship between the target value of brake torque and the target value of brake fluid pressure is preset. Based on the calculated target value of brake fluid pressure, the drive control unit 92 sets a target flow rate of brake fluid to be supplied from the master cylinder 14 to the brake fluid pressure control unit 20. For example, the drive control unit 92 may set the target flow rate of brake fluid by referring to map information in which the relationship between the target value of brake fluid pressure and the target flow rate is preset.

[0079] The drive control unit 92 may set a target flow rate according to the difference between the current brake fluid pressure and the target value of the brake fluid pressure. The current brake fluid pressure may alternatively be the pressure value detected by the fluid pressure sensor 24. If a brake fluid pressure sensor that detects the brake fluid pressure of one of the wheel cylinders 38 is provided in addition to the fluid pressure sensor 24, the pressure value detected by the brake fluid pressure sensor may be used instead of the fluid pressure sensor 24.

[0080]

[0057] The drive control unit 92 outputs a control signal to the drive circuit of the pump motor 61 of the brake fluid pressure control unit 20 in accordance with the set target flow rate, thereby driving the motor pumps 63a, 63b. As a result, brake fluid is supplied from the master cylinder 14 into the brake fluid pressure control unit 20, and the brake fluid is supplied to the wheel cylinders 38 of each wheel 3. The drive control unit 92 also controls the drive of each control valve (34, 36, 54, 58) to adjust the brake fluid pressure generated in the wheel cylinders 38 of each wheel 3.

[0081] [ 0 0 5 8 ]

[0082] (APB control unit)

[0083] The APB control unit 93 controls the operation of the APB device. For example, when the brake pedal 11 is depressed and a predetermined time has elapsed since the vehicle speed became zero, the APB control unit 93 outputs an operation command to the APB device 130. Furthermore, when the brake pedal 11 is released while the APB device 130 is operating, the APB control unit 93 outputs a command to the APB device 130 to cancel operation.

[0084] However, the processing contents of the APB control unit 93 are not particularly limited. For example, the APB control unit 93 may output an activation command to the APB device 130 when the driver turns on the activation switch of the APB device 130, and may output a command to cancel the operation of the APB device 130 when the driver turns off the activation switch of the APB device 130.

[0085] [ 0 0 6 0 ]

[0086] (Safety function unit) The safety function unit 94 stops the automatic brake control function by the brake fluid pressure control unit 20 when the voltage of the main power supply 5 and auxiliary power supply 7 that supply current to the brake fluid pressure control unit 20 drops. The safety function unit 94 stops the automatic brake control function by the brake fluid pressure control unit 20 when a drop in the voltage of the main power supply 5 or auxiliary power supply 7 makes it impossible to generate appropriate braking force on each wheel 3. In addition, the safety function unit 94 sends information to the driving assistance device 110 and other control devices indicating that the automatic brake control function has been stopped, and prohibits the execution of control that uses the automatic brake control function.

[0087]

[0061] When there is no abnormality in the main power supply 5 and current can be supplied from the main power supply 5 to the brake fluid pressure control unit 20, the safety function unit 94 monitors the voltage of the main power supply 5 and stops the automatic brake control function when the voltage of the main power supply 5 falls below a predetermined minimum value. Also, when an abnormality occurs in the main power supply 5 and the power source of the brake fluid pressure control unit 20 has been switched from the main power supply 5 to the auxiliary power supply 7, the safety function unit 94 monitors the voltage of the auxiliary power supply 7 and stops the automatic brake control function when the voltage of the auxiliary power supply 7 falls below a predetermined minimum value.

[0088] [ 0 0 6 2 ]

[0089] (First Determination Unit) The first determination unit 95 determines the activation state of the automatic brake control function that automatically controls the brakes of the vehicle. Specifically, the first determination unit 95 determines the activation state of automatic driving control at a level where a computer-based system is responsible, or the activation state of remote control where the driver remotely controls the vehicle via a mobile device. In this embodiment, the first determination unit 95 determines the activation state of the automatic brake control function based on information indicating the activation state of the automatic brake control function output from the driving assistance device 110.

[0090] [ 0 0 6 3 ]

[0091] (Second Determination Unit) The second determination unit 96 determines whether or not an abnormality has occurred in the main power supply 5. In this embodiment, the second determination unit 96 determines whether or not an abnormality has occurred in the main power supply 5 based on information transmitted from the power management device 120.

[0092] [ 0 0 6 4 ]

[0093] (Power supply switching unit) When the second determination unit 96 determines that an abnormality has occurred in the main power supply 5, the power supply switching unit 97 switches the power supply that supplies current to the brake fluid pressure control unit 20 to the auxiliary power supply 7.

[0094] [ 0 0 6 5 ]

[0095] (Output Limiting Unit) The output limiting unit 98 limits the upper limit of the rotation speed of the motor pump 63 of the brake hydraulic control unit 20 when the first determination unit 95 determines that the automatic brake control function is activated and the second determination unit 96 determines that an abnormality has occurred in the main power supply 5. By limiting the upper limit of the rotation speed of the motor pump 63, the output limiting unit 98 prevents the output current of the auxiliary power supply 7 from becoming excessive and prevents a drop in the voltage of the auxiliary power supply 7. In this way, the output limiting unit 98 prevents the automatic brake control function from being stopped by the safety function unit 94 when an abnormality occurs in the main power supply 5 while various controls using the automatic brake control function are being executed and the power source of the brake hydraulic control unit 20 has switched to the auxiliary power supply?

[0096] [ 0 0 6 6 ]

[0097] 4. Processing Operation Next, an example of a specific processing operation of the hydraulic pressure control device 90 according to this embodiment will be described. Below, processing operations related to the process of limiting the upper limit of the rotation speed of the motor pump 63 by the output limiting unit 98 (hereinafter also referred to as "output limiting process") will be described.

[0098]

[0067] Fig. 4 shows a flowchart of the output limiting process executed by the hydraulic control device 90. The output limiting process shown in Fig. 4 is executed continuously while the hydraulic brake system 1 is running.

[0099]

[0068] First, the first determination unit 95 of the hydraulic control device 90 determines whether the automatic brake control function that automatically controls the vehicle brakes is activated (step si1). For example, the first determination unit 95 determines whether remote operation control (remote parking control) that utilizes the automatic brake control function is being executed. If the first determination unit 95 does not determine that the automatic brake control function that automatically controls the vehicle brakes is activated (SI1 / NO), it repeats the determination of step S1!.

[0100]

[0069] On the other hand, if the first determination unit 95 determines that the automatic brake control function that automatically controls the vehicle brakes is activated (S11 / Yes), the second determination unit 96 determines whether an abnormality has occurred in the main power supply 5 (step S13). In this embodiment, the second determination unit 96 determines whether an abnormality has occurred in the main power supply 5 based on information transmitted from the power supply management device 120. If the hydraulic control device 90 can detect the output current and output voltage of the main power supply 5, the second determination unit 96 may have a function to determine an abnormality in the main power supply 5 by itself.

[0101]

[0070] If the second judgment unit 96 does not judge that an abnormality has occurred in the main power supply 5 (S13 / NO), the hydraulic control device 90 controls the drive of the brake hydraulic control unit 20 in accordance with the control being executed without restricting the output of the motor pump 63, thereby controlling the braking force of the vehicle (step S15). For example, when remote operation control is being executed, the target brake torque setting unit 91 of the hydraulic control device 90 sets the brake torque command value transmitted from the driving assistance device 11 as the brake torque target value, and the drive control unit 92 sets the target value of the brake hydraulic pressure for each wheel 3 based on the brake torque target value, and controls the drive of the pump motor 61 and each control valve (34, 36, 54, 58).

[0102]

[0071] On the other hand, if the second determination unit 96 determines that an abnormality has occurred in the main power supply 5 (S13 / Yes), the safety function unit 94 switches the power source of the brake fluid pressure control unit 20 from the main power supply 5 to the auxiliary power supply 7 (step S17). Specifically, the safety function unit 94 switches the relay switch on and off to electrically separate the main power supply 5 from the brake fluid pressure control unit 20, enabling power to be supplied from the auxiliary power supply 7 to the brake fluid pressure control unit 20.

[0103]

[0072] Next, the output limiting unit 98 limits the upper limit of the rotation speed of the motor pump 63 of the brake fluid pressure control unit 20 (step S19). Specifically, the output limiting unit 98 sets the maximum rotation speed of the pump motor 61 that drives the motor pump 63 to a preset limit value.

[0104]

[0073] Next, the hydraulic control device 90 controls the drive of the brake hydraulic control unit 20 in accordance with the control being executed, thereby controlling the braking force of the vehicle (step S21). For example, when remote operation control is being executed, the target brake torque setting unit 91 of the hydraulic control device 90 sets the brake torque command value transmitted from the driving assistance device 110 as the brake torque target value, and the drive control unit 92 sets the target value of the brake hydraulic pressure for each wheel 3 based on the brake torque target value, and controls the drive of the pump motor 61 and each control valve (34, 36, 54, 58).

[0105]

[0074] At this time, since the upper limit of the rotation speed of the pump motor 61 is limited, the increase gradient of the current supplied to the pump motor 61 is gentler than when the upper limit of the rotation speed of the pump motor 61 is not limited, so that the rotation speed of the pump motor 61 does not exceed the limit value during the period when the brake fluid pressure is being built up.

[0106]

[0075] Figures 5 and 6 are explanatory diagrams showing the difference in the increasing gradient of the supply current cur_act when the upper limit of the rotation speed of the pump motor 61 is limited when the brake fluid pressure is increased to a predetermined target value P_tgt.

[0107]

[0076] Figure 5 shows the target value P_tgt of the brake fluid pressure, the actual pressure value (model value) P_act, and the supply current cur_act when there is no upper limit on the rotation speed of the pump motor 61. When there is no upper limit on the rotation speed of the pump motor 61, the target value P_tgt of the brake fluid pressure increases at a steep rate to the target value P_tgt in a short time. Accordingly, in order to build up the brake fluid pressure in a short time, the supply current (inrush current) cur_act to the pump motor 61 increases abruptly, and the motor rotation speed reaches 10,000 rpm.

[0108]

[0077] When the brake fluid pressure control unit 20 receives current from the main power supply 5, the capacity of the main power supply 5 is large, so the voltage of the main power supply 5 does not drop significantly. Therefore, the automatic brake control function is not stopped by the safety function unit 94. On the other hand, when the brake fluid pressure control unit 20 receives current from the auxiliary power supply 7, the capacity of the auxiliary power supply 7 is small. The gradient of increase when increasing to P_tgt is gentler than in the case of Figure 5. As a result, the gradient of increase in the current (inrush current) cur-act supplied to the pump motor 6! to build up brake fluid pressure is gentler, the maximum value of the supply current (inrush current) cur-act is suppressed, and the maximum motor rotation speed is also suppressed to 6,000 rpm.

[0109] Therefore, even when the brake fluid pressure control unit 20 receives current from the auxiliary power supply 7, the voltage of the auxiliary power supply 7 does not drop significantly. This prevents the safety function unit 94 from stopping the automatic brake control function.

[0110]

[0080] The hydraulic pressure control device 90 repeatedly executes the processes of steps S11 to S21. This prevents the safety function unit 64 from stopping the automatic brake control function even if an abnormality occurs in the main power supply 5 and the power source of the brake hydraulic pressure control unit 20 is switched to the auxiliary power supply 7 while the automatic brake control function, which is mainly the responsibility of a computer system, is running.

[0111] [ 0 0 8 1 ]

[0112] <5. Effects> As described above, according to this embodiment, when it is determined that the automatic brake control function is activated and that an abnormality has occurred in the main power supply 5, the hydraulic control device 90 limits the upper limit of the rotation speed of the motor pumps 63a, 63b of the brake hydraulic control unit 20. As a result, when the brake hydraulic control unit 20 is controlled by receiving current from the auxiliary power supply 7, which has a smaller capacity than the main power supply 5, the increase gradient of the inrush current to the pump motor 61 when building up the brake hydraulic pressure is gentle. Therefore, it is possible to prevent the safety function unit 94 from stopping the automatic brake control function. As a result, it is possible to prevent the vehicle from being unable to stop and colliding with another vehicle, etc.

[0113]

[0082] Furthermore, according to this embodiment, the automatic brake control function is a remote parking control that automatically performs parking of the vehicle by remote operation. Therefore, even if an abnormality occurs in the main power supply 5 after the driver leaves the vehicle and remote parking control is started, the automatic brake control function due to the current supplied from the auxiliary power supply 7 can be prevented from being stopped.

[0114]

[0083] Furthermore, according to this embodiment, the hydraulic control device 90 includes an APB control unit 93 that performs automatic parking brake control to activate the parking brake of the vehicle when the vehicle is stopped. Therefore, even if an abnormality occurs in the main power supply 5, the operation of the parking brake of the vehicle can be controlled by power from the auxiliary power supply 7, and even if the auxiliary power supply 7 is connected to the brake hydraulic control unit 20, the safety function unit 94 can prevent the automatic brake control function from being stopped.

[0115]

[0084] Although preferred embodiments of the present disclosure have been described in detail above with reference to the accompanying drawings, the present disclosure is not limited to such examples. It is clear that a person skilled in the art to which the present disclosure pertains can conceive of various modified or altered examples within the scope of the technical ideas set forth in the claims, and it is understood that these also naturally fall within the technical scope of the present disclosure.

[0116]

[0085] For example, in the above embodiment, the hydraulic control device 90 has the functions of the APB control unit 93 and the power supply switching unit 97, but the APB control unit 93 and the power supply switching unit 97 may be provided in another control device.

[0117]

[0086] In the above embodiment, automatic driving control and remote operation control (remote parking control) are exemplified as functions utilizing automatic braking control for which a computer-based system is responsible, but the functions are not limited to the above examples. The present disclosure is particularly effective in situations where the driver cannot depress the brake pedal.

[0118] [Explanation of symbols]

[0119] [ 0 0 8 7 ]

[0120] 1: Hydraulic brake system

[0121] 5: Main power

[0122] 7: Auxiliary power supply

[0123] 1 〇: Electric brake booster

[0124] 1 3: Push rod

[0125] 1 4: Master cylinder

[0126] 2 〇: Brake fluid pressure control unit

[0127] 9 〇: Hydraulic pressure control device

[0128] 9 1: Target brake torque setting section

[0129] 9 2: Drive control unit

[0130] 9 3: APB control unit (automatic parking brake control unit)

[0131] 9 4: Safety function section

[0132] 9 5: First judgment section

[0133] 9 6: Second judgment section

[0134] 9 7: Power supply switching section

[0135] 9 8: Output limiter

[0136] 1 〇〇: Booster control device

[0137] 1 1 〇: Driving assistance device

[0138] 1 20: Power management device

[0139] 1 3 0 : APB device

[0140] 1 4 0: Communication bus

Claims

[Document name] Scope of claims

1. An electric brake booster (10) for boosting the depression force of a brake pedal (11) applied by a driver to pressurize brake fluid in a master cylinder (14); a brake fluid pressure control unit (20) including a motor pump (63a, 63b) and a plurality of control valves (34, 36, 54, 58) and for adjusting a brake fluid pressure generated in each wheel (3) of a moving body by the brake fluid supplied from the master cylinder (14); a main power source (5) electrically connected to the electric brake booster (10) and the brake fluid pressure control unit (20) for supplying power to the electric brake booster (io) and the brake fluid pressure control unit (20); and an auxiliary power source (61) connected to the brake fluid pressure control unit (20) for supplying power to the brake fluid pressure control unit (20) when an abnormality occurs in the main power source (5). A brake hydraulic pressure control unit in a hydraulic brake system (1) having an auxiliary power source (7). a first determination unit (95) for determining an activation state of an automatic brake control function for automatically controlling brakes of the moving body; a second determination unit (96) for determining whether an abnormality has occurred in the main power supply (5); and an output limiting unit (98) for limiting an upper limit of a rotation speed of the motor pump (63 a, 63 b) of the brake hydraulic control unit (20) when it is determined that the automatic brake control function is activated and that an abnormality has occurred in the main power supply (5).

2. The hydraulic control device according to claim 1, wherein the automatic brake control function is a remote parking control that automatically performs parking operation of the moving body by remote operation.

3. The hydraulic control device according to claim 1, further comprising an automatic parking brake control unit (93) that performs automatic parking brake control to activate a parking brake of the moving body when the moving body is stopped.

4. An electric brake booster (10) for boosting the depression force of a brake pedal (11) applied by a driver to pressurize brake fluid in a master cylinder (14); a brake fluid pressure control unit (20) including a motor pump (63a, 63b) and a plurality of control valves (34, 36, 54, 58) and for adjusting a brake fluid pressure generated in each wheel (3) of a moving body by the brake fluid supplied from the master cylinder (14); a main power source (5) electrically connected to the electric brake booster (10) and the brake fluid pressure control unit (20) for supplying power to the electric brake booster (io) and the brake fluid pressure control unit (20); and an auxiliary power source connected to the brake fluid pressure control unit (20) for supplying power to the brake fluid pressure control unit (20) when an abnormality occurs in the main power source (5). (7) and the brake hydraulic pressure control unit in a hydraulic brake system (1) comprising: A control method for controlling driving of a brake fluid pressure control unit (20), comprising: a step (S11) of judging an activation state of an automatic brake control function that automatically controls brakes of the moving body; a step (S13) of judging whether or not an abnormality has occurred in the main power supply (5); and a step (S19) of restricting an upper limit of a rotation speed of the motor pump (63a, 63b) of the brake fluid pressure control unit (20) when it is judged that the automatic brake control function is in an activated state and that an abnormality has occurred in the main power supply (5).

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